Technical Report

Algal Biomass Does it save the world?

Short reflections

2009

The technical potential of macro- and micro-algae for biomass production and greenhouse gas abatement has been recognised for many years, given their ability to use carbon dioxide and the possibility of their achieving higher productivities than land-based crops. Biofuel production from these marine resources, whether use of biomass or the potential of some species to produce high levels of oil, is now an increasing discussion topic. There are multiple claims in this sector but the use of algae as an energy production system is likely to have to be combined with waste water treatment or uptake of nutrients and minerals from polluted natural resources and co-production of high value products for an economic process to be achieved. These current biofuel discussions illustrate two issues. First, the potential broad utility of these organisms, that are capable of multiple products, ranging from energy, chemicals and materials to applications in carbon sequestration and waste water remediation. Second, the need for a robust evidence base of factual information to validate decisions for the strategic development of algae and to counter those claims made on a solely speculative basis to support commercial investment.

Photosynthetic macro-algae or micro-algae can grow both in salt or fresh water . Macro-algae or “seaweeds” are multicellular plants. They are often fast growing and can reach sizes of up to 60 m in length. They are classified into three broad groups based on their pigmentation: i) brown seaweed (Phaeophyceae); ii) red seaweed (Rhodophyceae) and iii) green seaweed (Chlorophyceae). Seaweeds are mainly utilised for the production of food and the extraction of hydrocolloids.

Microalgae are microscopic organisms. The three most important classes of micro-algae in terms of abundance are the diatoms (Bacillariophyceae), the green algae (Chlorophyceae), and the golden algae (Chrysophyceae). Diatoms are the dominant life form in phytoplankton and probably represent the largest group of biomass producers on earth. Green algae are especially abundant in fresh water. The main storage compound of these algae is starch, although oils can also be produced. The golden algae are similar to the diatoms and produce oils and carbohydrates.